Technical Field
The invention relates to apparatus and methods for projecting light images on reflective viewing screens.
Discussion of the Related Art
This section introduces aspects that may be helpful to facilitating a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light. The statements of this section are not to be understood as admissions about what is in the prior art or what is not in the prior art.
One type of image projector is based on a two-dimensional (2D) array of tiltable mirrors. The 2D array is illuminated by an incoherent light source. In the array, each mirror reflects part of the illumination light in a manner that depends on the mirror's orientation. The orientation of each mirror is controlled by a corresponding micro-electrical mechanical system (MEMS) actuator. The MEMS actuator tilts the corresponding mirror to reflect illumination light either towards a viewing screen or away from the viewing screen. That is, each MEMS actuator operates the corresponding mirror in an ON/OFF manner. The mirror is ON when it is tilted to specularly reflect a light spot to the viewing screen and is OFF when it is tilted to specularly reflect a light spot away from the viewing screen. Such tilting-mirror type image projectors can produce a variety of specularly reflected spot images.